1) Field of the Invention
The present invention relates to water-containing external preparations which contain corticosteroid, and more specifically to water-containing external preparations which contain deprodone propionate as an effective ingredient, can exhibit its effects to the maximum extent and over a prolonged period of time, do not have skin irritation, and are physicochemically stable.
2) Description of the Related Art
Corticosteroids have heretofore been employed widely as remedial agents in the field of dermatology because they exhibit even in a small amount strong therapeutic effects for inflammatory and allergic skin diseases and have fastacting property compared with other medicaments.
The corneum in the surface of the skin however inherently functions as a barrier in order to prevent penetration of foreign substances from the outside into the body. This has led to the problem that sufficient percutaneous absorption cannot be achieved with an external preparation containing a corticosteroid ingredient simply mixed in a base which has conventionally been employed in external preparations.
To improve this problem, various percutaneous absorption promoters such as 1-dodecylazacycloheptan-2-one, dimethylsulfoxide and dimethylformamide have been used in recent years. These promoters are however not considered sufficient in safety and feeling of use.
It is also practiced to use a corticosteroid having strong effects so as to tentatively improve the percutaneous absorption or to increase the concentration of a corticosteroid so as to increase the therapeutic effects. These methods are however accompanied by the problem of side effects because the influence to the whole body or a part thereof increases in proportion to the effects and concentration of the corticosteroid.
It has therefore been desired to develop a corticosteroid-containing ointment which has high curative effects and which gives less side effects to the whole body or a part thereof and has higher safety.
It is however to be noted that the curative effects of an external preparation significantly vary depending on the kind of its base and the like even when the external preparation contains the same effective ingredient at the same concentration and an external preparation having excellent curative effects and little side effects can be obtained for the first time when its effective ingredient and its base match well in physicochemical properties.